Ich schreib mir gerade meiner eigenen TGALader, und hab da mal eine Frage:
Wie kriege ich die Palettengröße her, wenn PictureType = 1 (mit Palette, unkomprimiert) ist?
Danke.

]]>https://www.c-plusplus.net/forum/topic/171458/tga-mit-paletteRSS for NodeMon, 06 Jul 2026 10:22:44 GMTThu, 25 Jan 2007 15:10:00 GMT60Ich schreib mir gerade meiner eigenen TGALader, und hab da mal eine Frage:
Wie kriege ich die Palettengröße her, wenn PictureType = 1 (mit Palette, unkomprimiert) ist?
Danke.

]]>https://www.c-plusplus.net/forum/post/1216954https://www.c-plusplus.net/forum/post/1216954Thu, 25 Jan 2007 15:10:00 GMT-------------------------------------------------------------------------------- DATA TYPE 1: Color-mapped images. | _______________________________________________________________________________| | Offset | Length | Description | |--------|--------|------------------------------------------------------------| |--------|--------|------------------------------------------------------------| | 0 | 1 | Number of Characters in Identification Field. | | | | | | | | This field is a one-byte unsigned integer, specifying | | | | the length of the Image Identification Field. Its range | | | | is 0 to 255. A value of 0 means that no Image | | | | Identification Field is included. | | | | | |--------|--------|------------------------------------------------------------| | 1 | 1 | Color Map Type. | | | | | | | | This field contains a binary 1 for Data Type 1 images. | | | | | |--------|--------|------------------------------------------------------------| | 2 | 1 | Image Type Code. | | | | | | | | This field will always contain a binary 1. | | | | ( That's what makes it Data Type 1 ). | | | | | |--------|--------|------------------------------------------------------------| | 3 | 5 | Color Map Specification. | | | | | | 3 | 2 | Color Map Origin. | | | | Integer ( lo-hi ) index of first color map entry. | | | | | | 5 | 2 | Color Map Length. | | | | Integer ( lo-hi ) count of color map entries. | | | | | | 7 | 1 | Color Map Entry Size. | | | | Number of bits in each color map entry. 16 for | | | | the Targa 16, 24 for the Targa 24, 32 for the Targa 32. | | | | | |--------|--------|------------------------------------------------------------| | 8 | 10 | Image Specification. | | | | | | 8 | 2 | X Origin of Image. | | | | Integer ( lo-hi ) X coordinate of the lower left corner | | | | of the image. | | | | | | 10 | 2 | Y Origin of Image. | | | | Integer ( lo-hi ) Y coordinate of the lower left corner | | | | of the image. | | | | | | 12 | 2 | Width of Image. | | | | Integer ( lo-hi ) width of the image in pixels. | | | | | | 14 | 2 | Height of Image. | | | | Integer ( lo-hi ) height of the image in pixels. | | | | | | 16 | 1 | Image Pixel Size. | | | | Number of bits in a stored pixel index. | | | | | | 17 | 1 | Image Descriptor Byte. | | | | Bits 3-0 - number of attribute bits associated with each | | | | pixel. | | | | Bit 4 - reserved. Must be set to 0. | | | | Bit 5 - screen origin bit. | | | | 0 = Origin in lower left-hand corner. | | | | 1 = Origin in upper left-hand corner. | | | | Must be 0 for Truevision images. | | | | Bits 7-6 - Data storage interleaving flag. | | | | 00 = non-interleaved. | | | | 01 = two-way (even/odd) interleaving. | | | | 10 = four way interleaving. | | | | 11 = reserved. | | | | This entire byte should be set to 0. Don't ask me. | | | | | |--------|--------|------------------------------------------------------------| | 18 | varies | Image Identification Field. | | | | Contains a free-form identification field of the length | | | | specified in byte 1 of the image record. It's usually | | | | omitted ( length in byte 1 = 0 ), but can be up to 255 | | | | characters. If more identification information is | | | | required, it can be stored after the image data. | | | | | |--------|--------|------------------------------------------------------------| | varies | varies | Color map data. | | | | | | | | The offset is determined by the size of the Image | | | | Identification Field. The length is determined by | | | | the Color Map Specification, which describes the | | | | size of each entry and the number of entries. | | | | Each color map entry is 2, 3, or 4 bytes. | | | | Unused bits are assumed to specify attribute bits. | | | | | | | | The 4 byte entry contains 1 byte for blue, 1 byte | | | | for green, 1 byte for red, and 1 byte of attribute | | | | information, in that order. | | | | | | | The 3 byte entry contains 1 byte each of blue, green, | | | | and red. | | | | | | | | The 2 byte entry is broken down as follows: | | | | ARRRRRGG GGGBBBBB, where each letter represents a bit. | | | | But, because of the lo-hi storage order, the first byte | | | | coming from the file will actually be GGGBBBBB, and the | | | | second will be ARRRRRGG. "A" represents an attribute bit. | | | | | |--------|--------|------------------------------------------------------------| | varies | varies | Image Data Field. | | | | | | | | This field specifies (width) x (height) color map | | | | indices. Each index is stored as an integral number | | | | of bytes (typically 1 or 2). All fields are unsigned. | | | | The low-order byte of a two-byte field is stored first. | | | | | -------------------------------------------------------------------------------- ]]>https://www.c-plusplus.net/forum/post/1217074https://www.c-plusplus.net/forum/post/1217074Thu, 25 Jan 2007 17:45:09 GMTJa danke, soweit war ich schon.
Aber das Problem ist folgendes:
Ich hab gerade ein Bild, mit Palette und unkomprimiert,
BitsPerPaletteEntry = 24 (also je ein byte für B,G und R),
und BytesPerPixel = 1.
Da frag ich mich, wie das gehen kann, gibt BytesPerPixel in diesem Fall die Größe der Indexe in die Palette an oder wie ist das dann?
Danke.

]]>https://www.c-plusplus.net/forum/post/1217763https://www.c-plusplus.net/forum/post/1217763Fri, 26 Jan 2007 19:29:27 GMTja, was sonst? wenn du pro pixel indizierst, ist jeder pixel nur so gross wie der index.

]]>https://www.c-plusplus.net/forum/post/1217934https://www.c-plusplus.net/forum/post/1217934Sat, 27 Jan 2007 06:21:43 GMT